186 ODOROGRAPHIA. 



Manilla Elemi is rich in essential oil. Fllickiger and Hanbuiy 

 state that on experiment they obtained by distilling 20 llxs. of the 

 resin with water, as much as 2 lbs. 13 ozs. (10 per cent.) of 

 fragrant colourless oil which was strongly dextrogyre. An oil of 

 elemi examined by Saint Claire Deville, was found by that eminent 

 chemist to be strongly L^evogyre.* These contradictory results 

 indicate that betw^een the essential oils of different sorts of elemi 

 there are as great differences observable in their physical properties 

 as between the oils of turpentine and copaiba. It is now known 

 that the principal constituent of ordinary oil of elemi is a dextro- 

 rotatory phellandrene and an optically inactive dipentene. The oil 

 also contains small quantities of polyterpenes and oxygenated 

 compounds, and it is known that the proportions of these bodies in 

 oil of elemi vary considerably according to tke botanical origin of 

 the Elemi resin. 



Oil of Elemi distilled from Elemi resin by Messrs. Schimmel has 

 been examined by Wallich, who found it to have a sp. gr. of 0*900 

 and to be dextro-rotatory. The examination showed it to contain 

 considerable quantities of a dextrogyre phellandrene, whilst in the 

 portion boiling between 175*^ and 180^ C. there is so large a 

 quantity of dipentene that the oil would appear suited for the 

 preparation of dipentene compounds. In addition, there was 

 found a large quantity of constituents having higher boiling 

 points, and the amyrin of the resin appeared to be represented in 

 the oil. 



Pure Elemi is recognisable by the following specially distinctive 



tests : — 



1. — Soluble in chloroform and ether, the latter solution not 

 being rendered turbid by alcohol. 



2. — Only partially soluble in alcohol, and the filtered solution is 

 not precipitated by alcoholic plumbic acetate (1 in 10). 



3. — A portion of the alcoholic solution evaporated leaves a 

 residue insoluble in boiling sodium carbonate. 



4. — The alcoholic and chloroform solutions are coloured violet 

 respectively by alcohol saturated with dry hydrochloric acid gas 

 and by bromine in chloroform (1 in 20). (Muter). 



* Comptes Rendus, xii., p. 184. 



